Are you 100% sure he didn't use any discs after he bridged the unlock pads? He must have had the xbox on a network (either at his house, shop, your house and he was on a laptop maybe?)...Either way, he had to some have gotten a different bios onto the xbox to flash it...Like other said, he probably just flashed from evox (but if he put evox on he would have needed a disc)....He used a disc at some point, u just didn't catch it...
The process is:
1. Unlock the tsop by brindging the pads
2. Exploit in to the xbox to gain FTP access (this is when u use 007, MA, or splinter cell and a gamesave)
3. Now u can either run raincoat to flash the tsop, or another similar tsop flash utility, or upload a bios into the c folder and flash from evox.
4. Install a dashboard (like evox or whatever)
Done.